K
Khách

Hãy nhập câu hỏi của bạn vào đây, nếu là tài khoản VIP, bạn sẽ được ưu tiên trả lời.

14 tháng 7 2019

75x : 49 = 728

=> 75x : 72 = 728

=> 75x - 2    = 28

=>   5x - 2  = 28

=>   5x        = 30

=>     x        = 30 : 5

=>     x        = 6

b) 2x - 5 = 27

=> 2x     = 27 + 5

=> 2x     = 32

=> 2x     = 25

=>   x     = 5

c) (x4)5 = x

=> x4.5 = x

=> x20  = x

=> x20 - x = 0

=> x(x19 - 1) = 0

=> \(\orbr{\begin{cases}x=0\\x^{19}-1=0\end{cases}}\)=> \(\orbr{\begin{cases}x=0\\x^{19}=1\end{cases}}\)=> \(\orbr{\begin{cases}x=0\\x^{19}=1^{19}\end{cases}}\)=> \(\orbr{\begin{cases}x=0\\x=\pm1\end{cases}}\)

Vậy \(x\in\left\{-1;0;1\right\}\)

\(a,7^{5x}:49=7^{28}\)

\(7^{5x}:7^2=7^{28}\)

\(7^{5x-2}=7^{28}\)

\(\Rightarrow5x-2=28\)\(\Rightarrow5x=30\)\(\Rightarrow x=6\)

\(b,2^x-5=27\)\(\Rightarrow2^x=32\)\(\Rightarrow2^x=2^5\Rightarrow x=5\)

\(c,\left(x^4\right)^5=x\)

\(\Rightarrow x^{20}=x\)

\(\Rightarrow\orbr{\begin{cases}x=0\\x=1\end{cases}}\)

27 tháng 9 2021

5 + ( x + 27 ) = 64

      ( x + 27 ) = 64 - 5      ( x + 27 ) = 59       x             = 59 - 27       x             = 32
27 tháng 9 2021

a) \(\Rightarrow x+27=59\Rightarrow x=32\)

b) \(\Rightarrow x-2=39\Rightarrow x=41\)

c) \(\Rightarrow x+5=-322\Rightarrow x=-327\)

d) \(\Rightarrow5x=35\Rightarrow x=7\)

e) \(\Rightarrow4\left(x-5\right)=56\Rightarrow x-5=14\Rightarrow x=19\)

f) \(\Rightarrow15+x=37\Rightarrow x=22\)

g) \(\Rightarrow7\left(13-x\right)=35\Rightarrow13-x=5\Rightarrow x=8\)

h) \(\Rightarrow10\left(x+1\right)=100\Rightarrow x+1=10\Rightarrow x=9\)

21 tháng 8 2021

1) \(\left(3x+2\right)^2-4\\ =\left(3x+2\right)^2-2^2\\ =\left(3x+2-2\right)\left(3x+2+2\right)\\ =3x.\left(3x+4\right)\)

2) \(4x^2-25y^2=\left(2x\right)^2-\left(5y\right)^2=\left(2x-5y\right)\left(2x+5y\right)\)

3) \(4x^2-49=\left(2x\right)^2-7^2=\left(2x-7\right)\left(2x+7\right)\)

4) \(8z^3+27=\left(2z\right)^3+3^3=\left(2z+3\right)\left(4z^2+6z+9\right)\)

5) \(\dfrac{9}{25}x^4-\dfrac{1}{4}=\left(\dfrac{3}{5}x^2\right)^2-\left(\dfrac{1}{2}\right)^2=\left(\dfrac{3}{5}x^2-\dfrac{1}{2}\right)\left(\dfrac{3}{5}x^2+\dfrac{1}{2}\right)\)

6) \(x^{32}-1\\ =\left(x^{16}\right)^2-1^2\\ =\left(x^{16}-1\right)\left(x^{16}+1\right)\\ =\left(x^8-1\right)\left(x^8+1\right)\left(x^{16}+1\right)\\ =\left(x^4-1\right)\left(x^4+1\right)\left(x^8+1\right)\left(x^{16}+1\right)\\ =\left(x^2-1\right)\left(x^2+1\right)\left(x^4+1\right)\left(x^8+1\right)\left(x^{16}+1\right)\\ =\left(x-1\right)\left(x+1\right)\left(x^2+1\right)\left(x^4+1\right)\left(x^8+1\right)\left(x^{16}+1\right)\)

1: \(\left(3x+2\right)^2-4=3x\left(3x+4\right)\)

2: \(4x^2-25y^2=\left(2x-5y\right)\left(2x+5y\right)\)

3: \(4x^2-49=\left(2x-7\right)\left(2x+7\right)\)

4: \(8z^3+27=\left(2z+3\right)\left(4z^2-6z+9\right)\)

5: \(\dfrac{9}{25}x^4-\dfrac{1}{4}=\left(\dfrac{3}{5}x^2-\dfrac{1}{2}\right)\left(\dfrac{3}{5}x^2+\dfrac{1}{2}\right)\)

21 tháng 12 2021

a: x=27

26 tháng 12 2021

a: x=27

6 tháng 8 2017

27000

6 tháng 8 2017

27000

6 tháng 1 2016

-2.(3x-5) + 3.(x+1) = 75x - 7

<=> -6x + 10 + 3x + 3 = 75x - 7

<=> -3x - 75x = -7 -3 -10

<=> -78x = -20

<=> x = 10/39

Vậy PT có tập nghiệm S = {10/39}.

a: \(x-\dfrac{10}{3}=\dfrac{7}{15}\cdot\dfrac{3}{5}\)

=>\(x-\dfrac{10}{3}=\dfrac{21}{75}=\dfrac{7}{25}\)

=>\(x=\dfrac{7}{25}+\dfrac{10}{3}=\dfrac{21+250}{75}=\dfrac{271}{75}\)

b: \(x+\dfrac{3}{22}=\dfrac{27}{121}\cdot\dfrac{9}{11}\)

=>\(x+\dfrac{3}{22}=\dfrac{243}{1331}\)

=>\(x=\dfrac{243}{1331}-\dfrac{3}{22}=\dfrac{123}{2662}\)

c: \(\dfrac{8}{23}\cdot\dfrac{46}{24}-x=\dfrac{1}{3}\)

=>\(\dfrac{8}{24}\cdot\dfrac{46}{23}-x=\dfrac{1}{3}\)

=>\(\dfrac{2}{3}-x=\dfrac{1}{3}\)

=>\(x=\dfrac{2}{3}-\dfrac{1}{3}=\dfrac{1}{3}\)

d: \(1-x=\dfrac{49}{65}\cdot\dfrac{5}{7}\)

=>\(1-x=\dfrac{49}{7}\cdot\dfrac{5}{65}=\dfrac{7}{13}\)

=>\(x=1-\dfrac{7}{13}=\dfrac{6}{13}\)